Combined freewheeling and power brake unit



Feb.'4, `1936. E. A. RocKwl-:LL

COMBINED FREEWHEELING AND POWER BRAKE UNIT Filed Feb. lO, 1935 '4 Sheets-Sheet 1 4 n J Y, s i DI... r Sm m mam n@ me@ @QH www,

Feb. 4, 1936. E; A. ROCKWELL 2,029,637

COMBINED FREEWHEELING AND POWER BRAKE UNIT Filed Feb. 10, 1955 4 Sheets-Sheet 2 L7/20577157 Edward [ffmc/iwal Feb 4, 1936. E. A. RocKwELL COMBNED FREEWHEELING AND POWER BRAKE UNIT 4 Sheeuts-Sheet 5 Filed Feb. l0, 1953 Feb. 4, 1936. E. A. RocKwELL COMBINED FREEWHEELING AND POWER BRAKE UNIT 4` Sheets-Sheet 4 Filed Feb. 1o, 1953 @verw/f Edy/@f @EUC/alge,

Patented Feb. 4, 1936 l UNITED STATES PATENT OFFICE;

COMBINED rnnnwnnanme AND Bowan BRAKE UNIT This invention relates to improvements in a combined free wheeling and power brake unit for motor vehicles. The improvements are particularly directed to the design of the casing and the arrangement of the parts therein which are adapted for association with the propeller shaft of a motor vehicle immediately in rear of the usual transmission. y

Previous disclosures have been made of power brake devices for motor vehicles according to which the pressure applied by'theoperator to the usual brake pedal is amplified through the momentum of the vehicle derived from rotation of the propeller shaft and the amplified force utilized in applying the Wheel brakes on all four wheels of the motor vehicle. Motor vehicles having so-called free wheeling devices have now come into` extensive use. In such a vehicle the propeller shaft or driven shaft of the vehicle is entirely freeto rotate faster than the speed at which it is being driven from the engine whereby the engine does not act as a brake to retard the momentum of the vehicle. When a free wheeling unit is employed it is allthe more desirable that the braking system of the vehicle be fully adequate to smoothly and quickly stop the vehicle.

, It is a purpose of the present invention to disclose an arrangement according to which a power brake unit is associated with a free wheeling unit whereby the power brake unit is always in readiness for actuation so long as the vehicle is in motion.

It is further an object of the present invention to combine the free wheeling unit and the power brake unit in the same casing which may be associated with the propeller shaft immediately in rear of the transmission of the vehicle.

It is further an object of the present invention to design'the parts of the free wheeling power brake unit in such a manner that a compact arrangement is obtained while at the same time preserving the desired strength and capacity of the parts-to carry out their intended .functions and further to enablevv convenient assembly of the parts and replacement thereof if found to be necessary.

It is a still further object of the invention to provide a fairly stiff return spring for normally holding thev power brake parts in' released positions and to connect the .emergency lever tof the brake linkage in such a manner that the operator does not need to overcomel the force of the stiff return spring when the brakes are manually set for parking.

Further objects and advantagesof the present improvements will be more readily apparent from the following description taken in connection with the attached drawings, in which Figurel is an elevation taken from one side of the power brake unit and controls therefor, a portion of the support'being shown in section;

Figure 2 is an elevation of the power brake unit taken from the other side and shown partially in section;

Figure 3 is a longitudinal section taken through `10l the power brake unit, and

Figure 4 is a transverse section taken through the power brake unit.

In the drawings, referring particularly to Figure 3, a portion of the transmission casing is indicated 15 I0. The transmission driving shaft I2 extends through the rear wall of the transmission casing I0 and is rotatably supported by the ball-bearing unit I4. The casing for the power brake and the freewheeling unit is composed'of two parts. 20 a body casing I6 and an end cover I8. The casing part I6 is secured to the transmission lcasing I8 and serves to hold the bearing I4 in place by a ring 20. The end of the shaft I2 which protrudes into the casing I6 is formed 25 with exterior straight splines 22 and is counterbored as at 24 to receive a reduced end 26 of the drive shaft 28.

The end 26 of drive shaft 28 is supported by the lroller bearings 30 which are received in the 30 counter-bored portion 24 of the shaft I2 and surround the end 26 of the shaft 28. The shaft 28 is provided with straight exterior splines 32. A flanged drive collar 34 is secured to the rear end of the shaft 28 by nut 36. The hub 38 of 35 the flanged collar 34 is forced into abutment with the inner race ring of a ball bearing unit 48 which supports the rear end of shaft 28 for rotation. in the cover part I8 of the casing. An oil sealing unit 42 is positioned in the open end 40 of the casing 'part I8 to surround the hub 38 of the ange drive collar 34 in sealing relation therewith.

The outer race ring of the ball bearing unit v4I) is held in position by a ring 44 seated in a 45 groove of the casing part I8 and the inner race ring of the ball lbearing unit 48 is forced by the hub 38 against a ring 46 carried in a groove of the shaft 28.

The shaft I2 is connected to the shaft 28 50 through a free wheeling unit, which may be of any desirable construction, but, as partially disclosed,` includes a gear member 48 splined to the shaft'28, held in position by a ring 50 seated in a groove of shaft 28 and serving to retain and 55 position the speedometer worm 62 which abuts against the rear side of member 48 and is retained in position by a. ring 64 carried by a groove in shaft 28.

The shaft I2 carries a drive member 66 which is adapted to transmit rotation in one direction only to internal gear member 58 through locking rollers 68. 'Ihe gear 58 is in mesh at its rear end with gear 48 through teeth 62. A slidable gear 64 is adapted to be moved to lock the free wheeling unit. and positively transmit rotation from shaft I2 to shaft 28 in either direction of rotation. It will be noted that the free wheeling unit occupies a space in the casing part I6 immediately in the rear of the transmission casing I8.

A non-rotatable laterally movable brake plate 65 is mounted within the casing uponl a pair of pins 66 at the top andra single pin 68 at the bottom. The upper pins 66 are supported in bosses 18 formed on the casing part I6 while the lower pin is received in the boss 12, also formed on the casing part I6. Compression springs, such as the spring 14, may be positioned to surround the pins 68 and 68 and to react between the casing part |8 and the brake plate 64 to hold the brake plate normally in released position. The brake plate 64 has a friction surface 16 opposed to the friction surface 18 formed on the casing part I8.

A normally rotatable but retardable braking member is positioned between the friction sur faces 16 and 18 and is composed of `a hub 88 having secured thereto by rivets 82 a. pair of disk members 84-88 which have attached to their marginal edges a pair of fabric friction rings 88 and 88. It will be apparent that the lateral movement of the brake plate 84 will serve to frictionally retard the rotation of the braking element by gripping the friction rings 88 and 88 between the friction surfaces 16-18. The hub 88 is supported by and keyed for relative axial movement with respect to a sleeve 82 having exterior straight splines 94 and having an interior spiral thread 88. The spiral sleeve 82 is coupled to an inner sleeve 88 having an exterior spiral thread |88. The inner spiral sleeve 88 is mounted on and keyed for axial movement with respect to the shaft 28. Thrust collars are mounted adjacent the opposite ends of the spiral sleeves 82 and 88. Thus, at the rearward ends of the sleeves there is positioned a thrust collar unit composed of a ring |82 mounted to abut against the locking ring 46. On the forward side of the ring |82 is a cushioning element, such as a leather ring |84, and finally a pressure receiving ring |86. 'Ihe rings |82|84|86 are held together by an annular clamping member |88. Adjacent the forward ends of the sleeves 92--88 is a thrust collar unit composed of a supporting ring ||8 having a face adapted to contact the forward ends'of the sleeves 82-88 and serving as a mounting for the thrust bearing ||2 and a soft metal outer ring ||4 mounted on a bronze filler ||5, al1 of'which are held together by an annular clamping member ||6.

'I'he input to the power brake unit includes a yoke member ||8 above the shaft 28 having thrust portions |28 adapted to engage raised portions on the brake plate 64. The yoke rnember ||8 is rockably supported in the walls of the casing part |6 by a bearing portion |22 on one side and by a rock shaft bearing portion |24 on the other side, at which side,the rock shaft protrudes outwardly from the casing I8. The protruding end I 25 of the rock shaft has secured thereto an input lever arm |26. The bearing portion |24 is mounted in bearing sleeve' |26 positioned in casing I6 and provided withan oil seal |21 and cap piece |28. The bearing opening in the casing for pin |22 is closed by cap |3I.

'I'he output from the power brake unit includes a yoke member |28, the arms of which have thrust-receiving portions |38 disposed in substantially the same horizontal plane with but spaced radially inward from the thrust portion |28 of the yoke II8. The thrust receiving portions |38 are adapted to contact the thrust ring I|4 of the output thrust collar at the forward ends oi!` the spiral sleeves. The yoke |28 has a collar |32 keyed to the splines |34 of the output rock shaft |36 and the collar |32 is held against displacement along the rock shaft |36 by a pin |38 which extends through a boss 12 on casing part I8 to engage a slot |48 formed in the collar |32. The collar |32 also includes a depending arm |42 having a contact face |44 adapted to engage the front face |46 of the boss 12, as shown in dotted lines in Figure 2, to limit movement of the output means in an actuating direction. This prevents locking of or damage to the spiral sleeves upon excessive wear of the brake linings or breakage of the output linkage.

The output rock shaft I 38 is supported at its ends by a boss |48 formed on one side of the casing |6 and a boss |68 formed on the other side of the casing part |6. The' rock shaft |36 is held in place by `a nut |52 screwed to the protruding end |54.

The nut I 52 serves to retain a stamped lever arm/|56 pressed by a spring element |58 into engagement with a washer |59 andan oil sealing washer |6| fitted in a groove of the boss |58 and pressed into contact with the surface of the rock shaft |36. The rock shaft |36 protrudes at its other end outside of the casing, as shown at |68, and has mounted thereon, with provision for lost motion a double arm lever |62 having oppositely extending' arms |64 and |66 which may be connected to suitable brake rods or brake operating members.

The rock shaft |36 is formed with an enlargement |65 which, when the rock shaft is in position, presses against a sealing ring |61 mounted in a groove of the boss |48. The hub of the lever |62 is closed at its open end by a. disk |68. The chamber |18 within the casing I6 is nlled to a desired level with an oil suitable for lubrication of the free-wheeling unit and the power brake unit.

Referring to Figure 1, a brake pedal |16 is pivotally supported at |18 upon a bracket |88 mounted on the floor board |82. The upper end of the brake pedal has pivotally attached thereto an adjustable push rod 84 connected beneath the floor board to a lever |86, pivotally mounted at |88 upon the engine frame. The lever |86 is connected by pull rod |98 to the input lever arm |26 of the power brake unit. As shown, the pull rod |88 is connected to lever |86 at pivot |82 but a second connecting opening |84 is provided, which is spaced further from the axis of the pivot |88. Similarly the rod |88 is connected to input lever |28 at pivot |96 and a second connecting opening |88 is provided. By changing the points at which the pull rod |88 is respectively connected to the lever |86 and the, input lever |26, the range and action of the brake pedal may be somewhat modified to suit the desires of the operator. The pedal-controlled linkage is held in normal released position by the pull back spring 200 extending between the input lever |26 and a part of the chassis frame, indicated at 202. As shown in Figure l, the lever arm 56, which is xed to the output rock shaft |36, is held in normal released position by a stiff pull back spring 2M attached at one end to the transmission casing lil. 'A fairly stili return spring is required, particularly in cold weather, in order to fully release the .power brake parts and return the spiral sleeves to their normal positions. However, as will be later described the operator does not-need to pull through this stiff spring 204 in applying the brakes by the emergency'lever.

The freewheeling controls are illustrated in Figure l. A rod 206 extends from a clutch pedal (not shown) to the lever arm 208 which is connected to a locking pin (not shown), which cooperates with the shift rod (not shown) for the free wheeling gear iid. The lever 2I is manually operated by a cable control 2l l. Assuming the parts to be in free wheeling position, the gear B in Figure 3 will be disengaged from the gear 58 and in order to change to conventional drive, the operator releases the clutch, thereby transmitting movement to rod 126, to lever Eilil and releasing the shift rod for gear 6d. Thereupon the lever 2l@ is moved by the cable control 2 Il in order to directly move the gear shift rod against the iorce of a return spring (not shown). When the gear @il has become fully engaged with the gear 5B, the parts will-be locked in' position until the operator again desires to shift back to free wheeling. As shown in Figure l, the lever 293 is directly associated with the powerbrake casing and the lever 2l@ is partially enclosed by a housing 2i?, xed to the power brake housing. i

Figures l and 2 also disclose a support for the rear end of the power brake casing. A cross member 2id is a part of the chassis frame, having mounted thereon a rubber block 2id, upon which rests the rear end of the power brake casing. rll`he brake casing is held down against the rubber block 2 i8 by a bolt 2i@ threaded into the power brake casing, there being a rubber block 221i between the head of the bolt and the brace 2id. The power brake casing is free to have a slight movement in a vertical direction due to the resiliency of the rubber blocks 2lb and 22d.

Figure 2 illustrates the manner in which the output of the power brake is connected to the wheel brakes and also the emergency lever oonnections for applying the wheel brakes. As previously stated, the lever MS2 is mounted on output rock shaft i3d with provision for lost motion. The depending lever arm |66 is connected by a pull rod 222 to the front wheel brakes. The upwardly directed lever arm I6@ has pivotally fastened thereto a connection 224 to which is secured a tension transmitting cable 226, which passes through flexible conduit 228 having an abutment 23D fastened to the cover I8 of the power brake casing by pin 232. The emergency lever 23d is pivoted at 236 and is connected by lost motion link 238 to lever arm 64. The provisions of the slots 240 in the link 238 need not be fully described herein, since this feature is disclosed and'claimed in the Evans and Rockwell application Serial No. 571,050, filed October 26, 1931.

The construction and operation of the power brake unit, except for the improvements suitably pointed out above, is substantially the same as the disclosure in Rockwell Patent No. 1,896,377, issued February '7, i933.

I claim:

l. ln a power brake unit a easing, an output rock shaft rockably supported by the side walls of said casing,a yoke-shaped member mounted on said rock shaft within said casing and keyed to said rock shaft against relative rotation with respect thereto, and a pin extending through the bottom wall of said casing and engaging said yoke member to prevent lateral displacement with respect to said rock shaft.

2. In a power brake unit a casing, an output rock shaft pivotally supported by the side walls of said casing, a yoke member mounted on said rock shaft within said casing andV keyed thereto against relative rotation, said casing having an abutmen formed thereon and said yoke member having a depending portion adapted to act as a stop to limit movement ci said rock shaft by engaging said casing abutment.

3. In a power brake system for motor vehicles, a mechanical power brake unit associated with the propeller shaft at the rear of the transmission, an input rock shaft for said power unit, an output rook shaft for said power unit, a brake lever mounted on saidoutput rock shaft with provision for lost motion, resilient means acting upon said output rockshaft to normally hold said output rock shaft in released position independent of movement of said brake lever and manually operable means for actuating said brake lever independent o said output rock shaft.

fi. 1n a power brake linkage for motor vehicles, a mechanical power brake unit associated with the propeller shaft of the vehicle at the rear of the transmission, an input rock shaft associated with said power brake unit, an output rock shaft associated with said power brake unit, a lever arm fixed to one end of said output rock shaft on the exterior of said power brake unit, resilient means acting upon said lever arm to normally hold said output rock shaft in released position, a brake lever mounted upon the other end of said output rock shaft on the exterior of said power brake unit with provision for lost motion and' manually operable means for actuating said lever independent of said output rock shaft.

EDWARD A. ROCKWELL. 

